The tending of a stoma - i.e. of an artificial outlet for stool (ileostoma, colostoma) or urine (urostoma) - is effected nowadays mainly by means of disposable adhesive bags.
Apart from the (rare) allergy to the adhesive, the adhesive bags involve the disadvantage that when being replaced they tear off or "strip" the uppermost epithelium layers of the skin until it wets and becomes extremely susceptible to irritations and infections. Skin problems around the stomata render the application of adhesive bags impossible in many cases, above all when the stripped skin is additionally exposed to fermentatively aggressive excreta (ileostomy, urostomy) or infectious material (fistulae).
To protect the skin in the immediate vicinity of the stoma, there have been developed base plates of a hypoallergic material, comprising a thin elastic film on the outside of the base plate. The base plates may remain in the applied position for several days. Onto this artificial skin the bags are adhered and are also to be replaced there once or several times a day.
This solution is extremely convenient to the patient (all is flat and flexible) and theoretically represents actually the ideal solution. In practical use, however, there result serious disadvantages. During sitting and stooping, folds are forming in the base plate so that, when the bag is being replaced, an odor and liquid-tight closure is made impossible. Moreover, the covering film of the base plate, which is very thin so as to have as far as possible the elasticity of the skin, is often damaged upon stripping off a bag. The base plate thereby becomes unservicable and must prematurely be replaced.
To overcome these said disadvantages, it has therefore been suggested to glue directly onto the base plate the semi-rigid ring of a snap closure whose likewise semirigid counterpart is provided at the bag. The closure engages according to the snap-fastener principle and can be replaced. This system solves very well the replacement of the bags but involves other, very inconvenient disadvantages:
1. The closure becomes practically rigid by the junction of the two semi-rigid rings. This rigid closure is very uncomfortable during sitting and stooping - quite particularly when large-size stomata, requiring largesize closures, are involved. The closure exerts a painful pressure on the skin, it detaches, due to its rigidity, the base plate from the elastic skin and finally "uses up" the base plate so that it has to be replaced more often than would be necessary with a fully elastic closure.
2. On account of the inconveniences during wearing, the patient cannot be expected to put up with a ring larger than absolutely necessary. There is thus required a considerable number of ring sizes both for the base plate and for the bag (at present 5 sizes are commercially available). Production and distribution are thereby rendered more expensive.
3. The tending or care of the most critical place, namely the skin ring between the circumference of the stoma and the inner edge of the circular opening of the base plate - e.g. by means of a coating paste - is complicated if narrow snap rings are involved. Wide rings allow a good tendance of that critical skin ring but are bulky and very uncomfortable due to their rigidity.
4. Moreover, excreta are regularly gathering in the circular niche between base plate and snap ring. They can be remomved only with difficulty, decompose quickly and lead to additional undesirable odors. They render a clean replacement difficult or impossible.
5. When the bag is being replaced, the new bag must be connected to the ring on the side of the body by pressure. Since said ring is firmly attached to the base plate, it is not possible to exert a counterpressure with the fingers. The pressure necessary for effecting the connection therefore fully acts on the at first mostly very sensitive abdomen of the patient.
The original and correct concept of a flexible connection between base plate and bag has, on account of the difficulties in the bag replacement, been sacrificed thus in favor of a rigid connection, which admittedly enables a simple replacement but involves said disadvantages.
With the particular object to overcome the disadvantages stated above under 1. and 5., there has already been proposed a device (Produce Information "Two-Piece Ostomy System", Hollister Inc., March 1982 and U.S. Pat. No. 4,419,100 issued Dec. 6, 1983 to Alexander), in which the ring of the snap closure is not glued to the base plate but connected thereto through a connecting piece, which allows limited floating between the ring and the base plate. The connecting piece is extremely thin flat resilient, annular web, connected at its outer circumference to the external portion of the back of the snap ring. The connection to the base plate is provided in the central area of the disk around the central opening.
The connection between base plate and snap ring is in this known device still relatively rigid. In the rest position, the snap ring substantially lies directly against the base plate - an allround, even small space between base plate and ring is not provided in that arrangement.
Consequently, the pressure discomfort to the user during stooping and sitting remains substantially unchanged. Since the annular web is fastened to the base plate at its central portion around the central opening, the possibility for the user to enlarge the opening so as to adjust it to his individual requirements is very restricted. In this device, too, various sizes are thus necessary, which renders the production, distribution and use more complicated and expensive.
Moreover, from the fact that the annular web is fastened to the base plate at its central portion and that for the desired "floating" of the ring a considerable distance must exist between the inner adhesion point and the outer circumference of the web to which the ring is attached, it follows that a larger and thus more comfortable ring is required for a given stoma size compared with the previous art as described above. Also, the annular web needs to be made of a resilient material because a movement perpendicular to the base plate (resulting when the fingers are inserted between base plate and web) would not be possible with this construction, when using flexible but unresilient material.
Finally, the snap ring of that device comprises on its inner side the necessary undercut for holding the counterpiece, which represents an undesired soil-catcher. Soil is collecting furthermore between the inner region of the bottom side of the ring and the connecting piece.
As advantage of the device known from U.S. Pat. No. 4,419,100 there remains thus substantially only the fact that it is possible to tilt the ring so as to enable to put the fingers below the snap ring and to exert a counterpressure when pressing on the ring provided at the bag. However, due to the close fitting of the snap ring at the base plate, a pressure on the area surrounding the stoma cannot be completely avoided in that device either. In addition any movement with this extremely thin device is only possible by stretching the resilient web, what creates traction forces irritating just the critical peristomal area and tending to separate there the base plate from the skin. As regards the movability of the parts relative to each other, the desired reduction of the number of sizes of the product and the demands concerning the requirements for cleaning, much is still left, however, to be desired.